Stabilized leaded gasolines



Patented July 10, 1951 UNITED STATES PATENT OFFICE 2,50%, STABILIZED LIADED GASOLINES Ilerlchcl G. Cantrell,

Penney] Smith, wlllllllfllfll. and TN! L Pl-J-llmntoGlif Oil Corporation. Pittsburgh, Pa, a corporation of No Drawing. Application June 3, 1.41, Serial No. 752,268

4 Claims. (CI. 44-69) tendency to cause knocking in high compression gasoline engines. The tetra-ethyl lead is added to the gasoline in a quantity sufllcient to produce the desired anti-knock rating. In some cases a relatively small amount may be required while in other cases, for example, in the preparation of certain aviation grades of gasoline, a relatively large amount may be added. Gasoline to which a large amount of tetra-ethyl lead or other tetraalkyl lead has been added is often referred to as a a heavily leaded" gasoline.

Although tetra-alkyl lead compounds, and in particular tetra-ethyl lead. are eillcient for 1mparting anti-knock properties to gasoline, their employment is not entirely free from disadvantage. For one thing. leaded gasoline tends to develop a hazy appearance upon standing, particularly in the presence of strong sunlight. Fbr example, in direct sunlight in the summertime, leaded gasoline may develop a perceptible haziness after an hour or two of exposure, and longer periods of exposure result in a very marked haziness and precipitation. The formation of haze in gasoline is objectionable because the gasoline is not as marketable as a clear product; customers prefer a product which is crystal clear. A further and more important objection is that a reduction in the octane rating of the gasoline is frequently associated with haze formation; furthermore, damage is likely to occur in the fuel lines and carburetor.

In addition to haze formation in leaded gasolines, there is a tendency to deposit gummy or resinous materials on standing, this tendency being particularly noticeable under the influence of air and light. Gum formation, as with haze formation, is usually attended by a lowering in anti-knock rating and development of a yellow or brownish color. Gum formation is also observed in engines burning the leaded gasoline, with the result that ring and valve sticking 0001.11.

This invention has as an object the stabilization of leaded gasolines, especially heavily leaded gasolines, against haze formation.

It is a further object of this invention to protect leaded gasoline against the deposition of gum and resinous matter.

A still further object of this invention is the prevention of lowering of anti-knock rating in leaded gasollnes.

2 These and other objects are accomplished by the present invention wherein there is added to gasoline; containing a tetra-alkvl lead compound stabilizing at least one phenol represented by the structural formula:

E III RI! wherein R, R" and R' represent alkyl substituents, at least one of R and 3'' having at least 3 carbon atoms; and (2) at least one aaomethine lcompound represented by the structural formu a:

wherein R1 and R: represent an aromatic group.

We have found that the addition to gasolines of trisubstituted alkyl phenol compounds of the above type in conjunction with the aromatic azomethine compounds shown impart characteristics which could not be predicted from the separate use of each inhibitor.

The alkyl phenols used in accordance with our invention have the formula:

wherein R, R." and R' represent alkyl substituents, at least one of R and R' having at least 3 carbon atoms. Examples of such phenols are 2,4.6-tritertiarybutyl phenol; 2,6-ditertiarybutyl-i-secondarybutyl phenol; 2,6-ditertiarybutyl-i-methyl phenol; 2,6-ditertiarybutyl-3- methyl phenol; 4,6-ditertiarybutyl 2-methyl phenol; 2-isopropyl-4,6-dimethyl phenol; 2-tertiarybutyl-4,6-dimethyl phenol; 2-tertiary amyl- 4,6-dimethyl phenol; 4-methyl-2,6-diisopropyl phenol; 2,4,6-triisopropyl phenol; 2,4,6-tritertiaryamyl phenol; and 2-tertiarybutyi-4,6-ditertiaryamyl phenol. Either individual phenols or mixtures thereof may be used, especially the mixture of alkylated phenols obtained in accordance with U. S. Patent 2,149,759 patented March 7, 1937. to Cantrell. A very effective phenol is 2,4,6-tritertiarybutyl phenol.

The azomethine compounds used in accordance with our invention have the formula:

m-s=c-m wherein Br and R: are aromatic groups. They are preferably made in accordance with the procedure shown in U. 8. Patent 2,388,903 patented November 13, 1945. to Cantrell and Peters by con! 3 4 denrima rimaryarylammewithanaromatio mseomparilonofflieuninhibltedand aldehydeinthepresenooofamllamountof inhibitodpsolineltoiiowaz a a a g 1 l 1- nil. Mura mm..-|w|-- we m on 4 e. llmvyppt... bmvyppt... nuns-um p-dimeth! idine, Z-hydroxy-S-methyiboumlanillnQ. p-dimethvlaminobenzai-p-dim i t pdimethylaminobenmlaniline. dibenzal-p-phenyl- .1. I v dibenzal-o-tolidine. cinnamylideneaniline. cinnamylidenexylidine. mrfuralaniline. furiuralxylidine. furfural-p-toluidine. furfural-otolidine. furfural benzal-o-tolidine, and furfuracrylideneaniline.

For inhibiting base formation. gum formation and lowering of octane rating in leaded gasolines. small amounts of the above dmcribed phenols and azomethine compounds are suiiicient. Generally. from 0.001 to 0.1 per cent by weight of the phenols and from 0.001 to 0.1 per azomethine compounds. or from 3 to 300 pounds 01 the phenol per 1000 barrels of gasoline and from 3 to 300 pounds of the azomethine compound per 1000 barrels of gasoline are added. A barrel is equivalent to 42 gallons.

The following examples further invention:

Example I.-Twenty pounds of a mixture consisting of 60 per cent by weight of the mixture of alkylated phenols obtained in accordance with U. 8. Patent 2,149,759 and 40 per cent by weight of benzalxylidine were added to 1000 barrels of a motor fuel containing tetraethyl lead. The resulting motor fuel was stabilized against gum and base formation.

Example H.--Pift.v pounds of a mixture consisting of pounds of the mixture of alkylated phenols obtained in accordance with U. S. Patent 2,149,759 and pounds of benzallylidine were added to 1000 barrels of a leaded gasoline. Not only was haze formation eliminated. but the formotion of gummy decompodtion products or solid deposits on the spark plugs. piston rings and valves of a test engine operating on the inhibited gasoline was virtually eliminated. The inhibited gasoline thus permitted operation of the engine without the usual ring and valve sticking and eliminated gum and carbon deposits.

Example III.From an aviation gasoline base having an octane rating of 91 and containing 4.0 cc. of tetraeihlll lead per gallon. three inhibited motor fuels were made up as follows: Motor fuel 1 containing 12 pounds of flAfi-tritertianbutyl phenol per 1000 barrels of base gasoline; motor fuel 11 containing lbs. of bennixylidine per 1000 barrels of base gasoline; and motor fuel 111 containing 12 pounds 01 2.4.6-tritertiarvbuUi phenol per 1000 barrels of base gasoline and 50 pounds of bensalxylidine per 1000 barrels of base illustrate our cent by weight of the i markedofmotoriuelm.

inaccordaneewithourtnvmtiomover thsuninhibitedgasolinebaseaswellaaoverthe other inhibited motor fuels containing only a The phenoloranasomethinecompcundisclear. It

r BI" BI! wherein R, R" and 11' represent alkyl substituents, at least one of R and 11'" having at least 3 carbon atoms; and (2) at least one asomethine compound having the formula:

I! ar-N=c-nl wherein R1 and Rs represent aromatic groups.

2. A leaded gasoline in accordance with claim 1, wherein the phenol is present in an amount oi. from 0.001 to 0.1 per cent by weight of the gasoline, and the azomethine compound is present in an amount of from 0.001 to 0.1 per cent by weight of the gasoline.

3. A leaded gasoline containing stabilizing amounts 0! 2,4.0-tritertiarybutyl phenol and benzalxylidine.

4. A leaded gasoline containing per 1000 barrels of gasoline 12 pounds of 2.4,6-tritertiarybutyl phenol and 50 pounds of benralxylidine.

. G. SMITH.

TROY L. CANTRELL REFERENCES CITED Thefollowingrefereneesareofrecordinthe flleofthispatent:

UR'ITID STATE PATENTS 2,381,331 Walters Oct. 24, 19 

1. A LEADED GASOLINE CONTAINING STABILIZING AMOUNTS OF (1) AT LEAST ONE PHENOL HAVING THE FORMULA: 